In various connections there is a need for a door that can cover large openings, with the door being lightweight, simple in construction and inexpensive to manufacture.
Norwegian Patent 136,110 describes a door that has a hoisting wire for raising the door which is fed through the separate lateral braces and fastened to a lowermost lateral brace. When this door is raised, the first lateral brace is initially raised while the rest of the door is motionless until the lateral braces below are raised toward the upper lateral brace thereby resulting in the lateral braces being forced together and squeezing the fabric of the door therebetween causing a number of problems. In the closed position the individual lateral braces will load the fabric and thereby stretch the same and there is a general need to improve this existing type of door.